Lipid nanoparticle-mediated CRISPR/Cas9 gene editing and metabolic engineering for anticancer immunotherapy

Metabolic engineering of the tumor microenvironment has emerged as a new strategy.Lactate dehydrogenase A(LDHA)is a prominent target for metabolic engineering.Here,we designed a cationic lipid nanoparticle formulation for LDHA gene editing.The plasmid DNA delivery efficiency of our lipid nanoparticle formulations was screened by testing the fluorescence of lipid nanoparticles complexed to plasmid DNA encoding green fluorescence protein(GFP).The delivery efficiency was affected by the ratios of three components:a cationic lipid,cholesterol or its derivative,and a fusogenic lipid.The lipid nanoparticle designated formulation F3 was complexed to plasmid DNA co-encoding CRISPR-associated protein 9 and LDHA-specific sgRNA,yielding the lipoplex,pCas9-sgLDHA/F3.The lipoplex including GFP-encoding plasmid DNA provided gene editing in HeLa-GFP cells.Treatment of B16F10 tumor cells with pCas9-sgLDHA/F3 yielded editing of the LDHA gene and increased the pH of the culture medium.pCas9-sgLDHA/F3 treatment activated the interferon-gamma and granzyme production of T cells in culture.In vivo,combining pCas9-sgLDHA/F3 with immune checkpoint-inhibiting anti-PD-L1 antibody provided a synergistic antitumor effect and prolonged the survival of tumor model mice.This study suggests that combining metabolic engineering of the tumor microenvironment with immune checkpoint inhibition could be a valuable antitumor strategy.

A zwitterionic polymer-inspired material mediated efficient CRISPR-Cas9 gene editing

The typeⅡ prokaryotic CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR/Cas9) adaptive immune system is a cutting-edge genome-editing toolbox.However,its applications are still limited by its inefficient transduction.Herein,we present a novel gene vector,the zwitterionic polymer-inspired material with branched structure (ZEBRA) for efficient CRISPR/Cas9 delivery.Polo-like kinase 1 (PLK1) acts as a master regulator of mitosis and overexpresses in multiple tumor cells.The Cas9 and single guide sgRNA (sgRNA)-encoded plasmid was transduced to knockout Plk1 gene,which was expected to inhibit the expression of PLK1.Our studies demonstrated that ZEBRA enabled to transduce the CRISPR/Cas9 system with large size into the cells efficiently.The transduction with ZEBRA was cell line dependent,which showed~10-fold higher in CD44-positive cancer cell lines compared with CD44-negative ones.Furthermore,ZEBRA induced highlevel expression of Cas9 proteins by the delivery of CRISPR/Cas9 and efficient gene editing of Plk1 gene,and inhibited the tumor cell growth significantly.This zwitterionic polymerinspired material is an effective and targeted gene delivery vector and further studies are required to explore its potential in gene delivery applications.

Therapeutic gene editing strategies using CRISPR-Cas9 for theβ-hemoglobinopathies

With advancements in gene editing technologies,our ability to make precise and efficient modifications to the genome is increasing at a remarkable rate,paving the way for scientists and clinicians to uniquely treat a multitude of previously irremediable diseases.CRISPR-Cas9,short for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9,is a gene editing platform with the ability to alter the nucleotide sequence of the genome in living cells.This technology is increasing the number and pace at which new gene editing treatments for genetic disorders are moving toward the clinic.Theβ-hemoglobinopathies are a group of monogenic diseases,which despite their high prevalence and chronic debilitating nature,continue to have few therapeutic options available.In this review,we will discuss our existing comprehension of the genetics and current state of treatment forβ-hemoglobinopathies,consider potential genome editing therapeutic strategies,and provide an overview of the current state of clinical trials using CRISPR-Cas9 gene editing.

Harnessing CRISPR-Cas system diversity for gene editing technologies

The discovery and utilization of RNA-guided surveillance complexes,such as CRISPR-Cas9,for sequencespecific DNA or RNA cleavage,has revolutionised the process of gene modification or knockdown.To optimise the use of this technology,an exploratory race has ensued to discover or develop new RNA-guided endonucleases with the most flexible sequence targeting requirements,coupled with high cleavage efficacy and specificity.Here we review the constraints of existing gene editing and assess the merits of exploiting the diversity of CRISPR-Cas effectors as a methodology for surmounting these limitations.

Traceless photodegradable polymer cocoons for universal protein delivery and light-controlled gene editing

Polymer conjugation was found highly valuable in clinic to improve the bioavailability of protein therapeutics.However,it is still a tremendous challenge to achieve a complete release of original proteins from the conjugated hybrid under external stimulus to recover active proteins in the targeted tissue.Herein,we report a general light-controlled protein delivery methodology by weaving a photodegradable polymer cocoon around proteins,which could reliably protect them from degradation in the dark while efficiently releasing them under illumination without any residual atoms.The surface charge of the polymer shell is easily tunable to facilitate efficient cell uptake.The versatility of this strategy is demonstrated by the delivery of the Cas9/sg RNA complex that realized light-controlled gene editing both in vitro and in vivo,and such repertoire is of particular value in regard to minimizing the off-target toxicity of CRISPR-Cas9-based gene therapy.

CRISPR-based gene editing technology and its application in microbial engineering

Gene editing technology involves the modification of a specific target gene to obtain a new function or phenotype.Recent advances in clustered regularly interspaced short palindromic repeats(CRISPR)-Cas-mediated technolo-gies have provided an efficient tool for genetic engineering of cells and organisms.Here,we review the three emerging gene editing tools(ZFNs,TALENs,and CRISPR-Cas)and briefly introduce the principle,classification,and mechanisms of the CRISPR-Cas systems.Strategies for gene editing based on endogenous and exogenous CRISPR-Cas systems,as well as the novel base editor(BE),prime editor(PE),and CRISPR-associated transposase(CAST)technologies,are described in detail.In addition,we summarize recent developments in the application of CRISPR-based gene editing tools for industrial microorganism and probiotics modifications.Finally,the potential challenges and future perspectives of CRISPR-based gene editing tools are discussed.

Treatment of infectious diseases by in vivo gene editing

Gene editing is the specific modification of genome sequences at desired sites using technologies derived from zinc finger nucleases(ZFNs),transcription activator-like effector nucleases(TALENs)and clustered regularly interspaced short palindromic repeats(CRISPR)-CRISPR-associated(Cas)nuclease systems.It is a promising tool for the development of new treatment strategies for infectious diseases.Due to its higher editing efficiency and lower off-target effect,gene editing therapy mainly uses CRISPR Cas-derived tools to resist viral and non-viral infections.Here,we reviewed the recent research progress of gene editing in antiviral therapy(human immunodeficiency virus,hepatitis B virus,severe acute respiratory syndrome coronavirus 2,and human papillomavirus)and inhibition of infectious diseases that involve bacteria,fungi and parasites.

Molecular breeding of farm animals through gene editing

The rapid development of biotechnology has facilitated our understanding of the biological functions of candidate genes for important economic traits in farm animals.Molecular breeding by gene editing has greatly revolutionized the breeding of farm animals.Through gene editing and embryo manipulation,breeds with designed economic or disease-resistant traits can be readily generated.Along with this fast progress,the safety assessment of gene-edited farm animals has attracted public and regulatory attention.This review summarizes the research progress of gene editing in farm animals,focusing on performance improvement,disease resistance,bioreactors,animal welfare,and environmental friendliness.The limitations and future development of gene editing technology in farm animal breeding are also discussed.

A review of the literature on the use of CRISPR/Cas9 gene therapy to treat hepatocellular carcinoma

Noncoding RNAs instruct the Cas9 nuclease to site speifillyl cleave DNA in the CRISPR/Cas9 system.Despite the high incidence of hepatocellular carcinoma(HCC),the patient's outcome is poor.As a result of the emergence of therapeutic resistance in HCC patients,dlinicians have faced difficulties in treating such tumor.In addition,CRISPR/Cas9 screens were used to identify genes that improve the dlinical response of HCC patients.It is the objective of this article to summarize the current understanding of the use of the CRISPR/Cas9 system for the treatment of cancer,with a particular emphasis on HCC as part of the current state of knowledge.Thus,in order to locate recent developments in oncology research,we examined both the Scopus database and the PubMed database.The ability to selectively interfere with gene expression in combinatorial CRISPR/Cas9 screening can lead to the discovery of new effective HCC treatment regimens by combining clinically approved drugs.Drug resistance can be overcome with the help of the CRISPR/Cas9 system.HCC signature genes and resistance to treatment have been uncovered by genome-scale CRISPR activation screening although this method is not without limitations.It has been extensively examined whether CRISPR can be used as a tool for disease research and gene therapy.CRISPR and its applications to tumor research,particularly in HCC,are examined in this study through a review of the literature.

Ethical and legal implications of gene editing in plant breeding:a systematic literature review

Biotechnology policies and regulations must be revised and updated to reflect the most recent advances in plantbreeding technology. New Plant Breeding Techniques(NPBT) such as gene editing have been applied to address the myriad of challenges in plant breeding, while the use of NPBT as emerging biotechnological tools raises legal and ethical concerns. This study aims to highlight how gene editing is operationalized in the existing literature and examine the critical issues of ethical and legal issues of gene editing for plant breeding. We carried out a systematic literature review(SLR) to provide the current states of ethical and legal discourses surrounding this topic. We also identified critical research priority areas and policy gaps that must be addressed when designing the future governance of gene editing in plant breeding.

The concept of gene therapy for glaucoma:the dream that has not come true yet

Gene therapies,despite of being a relatively new therapeutic approach,have a potential to become an important alternative to current treatment strategies in glaucoma.Since glaucoma is not considered a single gene disease,the identified goals of gene therapy would be rather to provide neuroprotection of retinal ganglion cells,especially,in intraocular-pressure-independent manner.The most commonly reported type of vector for gene delivery in glaucoma studies is adeno-associated virus serotype 2 that has a high tro pism to retinal ganglion cells,res ulting in long-term expression and low immunogenic profile.The gene thera py studies recruit inducible and genetic animal models of optic neuropathy,like DBA/2J mice model of high-tension glaucoma and the optic nerve crush-model.Reported gene therapy-based neuroprotection of retinal ganglion cells is targeting specific genes translating to growth factors(i.e.,brain derived neurotrophic factor,and its receptor TrkB),regulation of apoptosis and neurodegeneration(i.e.,Bcl-xl,Xiap,FAS system,nicotinamide mononucleotide adenylyl transferase 2,Digit3 and Sarm1),immunomodulation(i.e.,Crry,C3 complement),modulation of neuroinflammation(i.e.,e rythropoietin),reduction of excitotoxicity(i.e.,Com KIlα)and transcription regulation(i.e.,Max,Nrf2).On the other hand,some of gene therapy studies focus on lowering intra ocular pressure,by impacting genes involved in both,decreasing aqueous humor production(i.e.,aquaporin 1),and increasing outflow facility(i.e.,COX2,prostaglandin F2a receptor,RhoA/RhoA kinase signaling pathway,MMP1,Myocilin).The goal of this review is to summarize the current stateof-art and the direction of development of gene therapy strategies for glaucomatous neuropathy.

CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes

Genome editing tools such as the clustered regularly interspaced short palindromic repeat （CRISPR）-associated system （Cas） have been widely used to modify genes in model systems including animal zygotes and human cells, and hold tremendous promise for both basic research and clinical applications. To date, a serious knowledge gap remains in our understanding of DNA repair mechanisms in human early embryos, and in the efficiency and potential off-target effects of using technologies such as CRISPR/Cas9 in human pre-implantation embryos. In this report, we used tripronuclear （3PN） zygotes to further investigate CRISPR/Cas9-mediated gene editing in human cells. We found that CRISPR/Cas9 could effectively cleave the endogenous β-globin gene （HBB）. However, the efficiency of homologous recombination directed repair （HDR） of HBB was low and the edited embryos were mosaic. Off-target cleavage was also apparent in these 3PN zygotes as revealed by the T7E1 assay and whole-exome sequencing. Furthermore, the endogenous delta-globin gene （HBD）, which is homologous to HBB, competed with exogenous donor oligos to act as the repair template, leading to untoward mutations. Our data also indicated that repair of the HBB locus in these embryos occurred preferentially through the non-crossover HDR pathway. Taken together, our work highlights the pressing need to further improve the fidelity and specificity of the CRISPR/Cas9 platform, a prerequisite for any clinical applications of CRSIPR/Cas9-mediated editing.

Multiplex gene editing in rice with simplified CRISPR-Cpf1 and CRISPR-Cas9 systems

The class 2 clustered regularly interspaced short palindromic repeat （CRISPR） systems have been widely used for simultaneous modification of multiple loci in plants. Traditionally, the type II CRISPR-Cas9 or type V CRISPR-Cpfl （also known as Cas12a） system is a two-component transcriptional unit （TCTU） in which the Cas9 or Cpf1 protein is expressed from an RNA polymerase （pol） II promoter, whereas the single guide RNA （sgRNA） is typically expressed from a Pol III promoter, such as U6 or U3 promoter.

Gene editing and its applications in biomedicine

The steady progress in genome editing, especially genome editing based on the use of clustered regularly interspaced short palindromic repeats(CRISPR) and programmable nucleases to make precise modifications to genetic material, has provided enormous opportunities to advance biomedical research and promote human health. The application of these technologies in basic biomedical research has yielded significant advances in identifying and studying key molecular targets relevant to human diseases and their treatment. The clinical translation of genome editing techniques offers unprecedented biomedical engineering capabilities in the diagnosis, prevention, and treatment of disease or disability. Here, we provide a general summary of emerging biomedical applications of genome editing, including open challenges. We also summarize the tools of genome editing and the insights derived from their applications, hoping to accelerate new discoveries and therapies in biomedicine.

Highly efficient,genotype-independent transformation and gene editing in watermelon(Citrullus lanatus)using a chimeric ClGRF4-GIF1 gene

Efficient genetic transformation has the potential to advance research and breeding in watermelon(Citrullus lanatus),but regeneration from tissue culture remains challenging.Previous work showed that expressing a fusion of two interacting transcription factors,GROWTH-REGULATING FACTOR4(GRF4)and GRF-INTERACTING FACTOR1(GIF1),improved regeneration in wheat(Triticum aestivum).By overexpressing a chimeric fusion of Cl GRF4 and Cl GIF1,we achieved highly efficient transformation in watermelon.Mutating the mi396 micro RNA target site in Cl GRF further boosted the transformation efficiency up to 67.27%in a genotype-independent manner.Cl GRF4-GIF1 can also be combined with clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)genome editing tools to achieve highly efficient gene editing in watermelon,which we used to successfully create diploid seedless watermelon.This research thus puts forward a powerful transformation tool for future watermelon research and breeding.

Efficient allelic replacement in rice by gene editing： A case study of the NRT1.1B gene

Summary Precise replacement of an existing allele in commercial cultivars with an elite allele is a major goal in crop breeding. A single nucleotide polymorphism in the NRT1.1B gene between japonica and indica rice is responsible for the improved nitrogen use efficiency in indica rice. Herein, we precisely replaced the japonica NRT1.1B allele with the indica allele, in just one generation, using CRISPR/Cas9 gene-editing technology. No additional selective pressure was needed to enrich the precise replacement events.

Large chromosomal segment deletions by CRISPR/LbCpf1-mediated multiplex gene editing in soybean

The creation of new soybean varieties has been limited by genomic duplication and redundancy.Efficient multiplex gene editing and large chromosomal segment deletion through clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein(Cas)systems are promising strategies for overcoming these obstacles.CRISPR/Cpf1 is a robust tool for multiplex gene editing.However,large chromosomal excision mediated by CRISPR/Cpf1 has been reported in only a few non-plant species.Here,we report on CRISPR/LbCpf1-induced large chromosomal segment deletions in soybean using multiplex gene targeting.The CRISPR/LbCpf1 system was optimized for direct repeat and guide RNA lengths in crispr RNA(crRNA)array.The editing efficiency was evaluated using LbCpf1 driven by the CaMV35S and soybean ubiquitin promoter.The optimized system exhibited editing efficiencies of up to 91.7%.Our results showed eight gene targets could be edited simultaneously in one step when a single eight-gRNA-target crRNA array was employed,with an efficiency of up to 17.1%.We successfully employed CRISPR/LbCpf1 to produce small fragments(<1 Kb)and large chromosomal segment deletions(10 Kb-1 Mb)involving four different gene clusters in soybean.Together,these data demonstrate the power of the CRISPR/LbCpf1 platform for multiplex gene editing and chromosomal segment deletion in soybean,supporting the use of this technology in both basic research and agricultural applications.

CRISPR/Cas9 gene editing and natural variation analysis demonstrate the potential for HvARE1 in improvement of nitrogen use efficiency in barley

Nitrogen is a major determinant of grain yield and quality.As excessive use of nitrogen fertilizer leads to environmental pollution and high production costs,improving nitrogen use efficiency(NUE)is fundamental for a sustainable agriculture.Here,we dissected the role of the barley abnormal cytokinin response1 repressor 1(Hv ARE1)gene,a candidate for involvement in NUE previously identified in a genome-wide association study,through natural variation analysis and clustered regularly interspacedshort palindromic repeats(CRISPR)/CRISPRassociated protein 9(Cas9)-mediated gene editing.Hv ARE1 was predominantly expressed in leaves and shoots,with very low expression in roots under low nitrogen conditions.Agrobacterium-mediated genetic transformation of immature embryos(cv.Golden Promise)with single guide RNAs targeting Hv ARE1 generated 22 T0 plants,from which four T1 lines harbored missense and/or frameshift mutations based on genotyping.Mutant are1 lines exhibited an increase in plant height,tiller number,grain protein content,and yield.Moreover,we observed a 1.5-to2.8-fold increase in total chlorophyll content in the flag leaf at the grain filling stage.Delayed senescence by 10–14 d was also observed in mutant lines.Barley are1 mutants had high nitrogen content in shoots under low nitrogen conditions.These findings demonstrate the potential of ARE1 in NUE improvement in barley.

Efficient generation of the mouse model with a defined point mutation through haploid cell-mediated gene editing

Generation of mouse models carrying a defined point mutation,especially disease-related point mutations,is of considerable interest for research in biology and medicine.The standard method based on embryonic stem cell（ESC）-mediated homologous recombination（HR）is time-and labor-consuming.

The CRISPR/Cas revolution continues: From efficient gene editing for crop breeding to plant synthetic biology

Since the discovery that nucleases of the bacterial CRISPR(clustered regularly interspaced palindromic repeat)-associated(Cas) system can be used as easily programmable tools for genome engineering,their application massively transformed different areas of plant biology. In this review, we assess the current state of their use for crop breeding to incorporate attractive new agronomical traits into specific cultivars of various crop plants. This can be achieved by the use of Cas9/12 nucleases for double-strand break induction,resulting in mutations by non-homologous recombinatr e-tion. Strategies for performing such experiments à from Rthe design of guide RNA to the use of different transformation technologies à are evaluated. Furtherweive-more, we sum up recent developments regarding the use of nuclease-deficient Cas9/12 proteins, as DNAbinding moieties for targeting different kinds of enzyme activities to specific sites within the genome. Progress in base deamination, transcriptional induction and transcriptional repression, as well as in imaging in plants, is also discussed. As different Cas9/12 enzymes are at hand, the simultaneous application of various enzyme activities, to multiple genomic sites, is now in reach to redirect plant metabolism in a multifunctional manner and pave the way for a new level of plant synthetic biology.